[Laboratory examinations in emergency cases: urea nitrogen].
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Blood Urea Nitrogen↗
Biomedical subjects
M Kitamura
Publications and source records attributed to M Kitamura.
[Contamination of specimens and its prevention in the continuous-flow system].
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Blood Urea Nitrogen↗
[Tests for alkaline phosphatase].
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Alkaline Phosphatase↗
Chemiluminescent immunoassay (CLIA) for salmon growth hormone (GH).
A highly sensitive and specific chemiluminescent immunoassay (CLIA) was developed for quantification of growth hormone (GH) in salmonid species. The CLIA for salmon GH was performed using the sandwich method with anti-GH IgG as the first antibody and chemiluminescent acridinium ester-labelled specific anti-GH F(ab')2 as the second antibody. The measurable range of salmon GH in the CLIA was 39-1250 pg/mL using a short assay (1 day) protocol and 3.9-125 pg/mL in a longer (2-day) assay. The dilution curve in the CLIA of serum from masu salmon (Oncorhynchus masou) was parallel to the standard curve of recombinant chum salmon (Oncorhynchus keta) GH. Seasonal changes of serum GH levels were measured in 1 year-old masu salmon cultivated in a pond from March to November. Their serum GH levels increased during smoltification from March to April, achieved a maximum level of 21 ng/mL in August, and then declined gradually to 11 ng/mL in October.
Animals↗
A new highly sensitive chemiluminescent assay of alkaline phosphatase using lucigenin and its application to enzyme immunoassay.
The chemiluminescent reaction of lucigenin with various reducing sugars and reducing compounds has been studied. It was found that dihydroxyacetone gave the most intense chemiluminescence (CL). We have developed highly sensitive chemiluminescent methods for alkaline phosphatase (ALP) based on the production of dihydroxyacetone using NADP+ or glycerol-3-phosphate as substrate. The detection limits for ALP using each substrate were 1.25 x 10(-19) mol/assay and 2.5 x 10(-19) mol/assay, and the coefficient of variation (n = 7) was 2.8% and 3.7%, respectively. We have also applied the method using NADP+ as substrate in enzyme immunoassays (EIA) for cholecystokinin (CCK) and human chorionic gonadotropin (hCG). CCK-8 (octapeptide sulphated form of a carboxy terminal fragment of CCK) concentrations released from alimentary canal of rat were assayed using the chemiluminescent EIA (CLEIA) and a fluorimetric EIA (ALP label). The correlation between CCK-8 values obtained by these methods was y = 1.04x + 18.21, r = 0.946, n = 28. hCG values in serum and in urine were measured. The correlation between hCG values in serum samples obtained using the CLEIA and a time-resolved fluoroimmunoassay (TR-FIA), and in urine samples obtained using the CLEIA and the fluorimetric EIA using ALP were satisfactory. The correlations were y = 1.00x - 0.04, r = 0.997 (n = 51) and y = 1.00x - 0.03, r = 0.999 (n = 10), respectively.
Acridines↗
Effect of hepatocyte growth factor on chronic rejection in rat renal allografts.
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Analysis of Variance↗
Stimulatory effect of PACAP on gastroduodenal bicarbonate secretion in rats.
The effects of pituitary adenylate cyclase activating polypeptides (PACAPs) on gastroduodenal HCO3- secretion were investigated in anesthetized rats and compared with those of vasoactive intestinal polypeptide (VIP). Under urethane anesthesia, a rat stomach mounted in an ex vivo chamber (in the absence of acid secretion) or a rat proximal duodenal loop was perfused with saline, and the HCO3- secretion was measured at pH 7.0 using a pH-stat method and by adding 10 mM HCl. Intravenous injection of PACAP-27 stimulated HCO3- secretion in a dose-dependent manner in the duodenum but not in the stomach; at 8 nmol/kg PACAP-27 increased the HCO3- secretion to maximal values of four times greater than basal levels, although this peptide had no effect on duodenal HCO3- secretion after intracisternal administration (1 nmol/rat). PGE2 (300 micrograms/kg, iv) significantly increased HCO3- secretion in both the stomach and the duodenum. The potency of duodenal HCO3- secretory action was in the following order; PACAP-27 > PACAP-38 = VIP, and that of PACAP-27 was about 100-fold greater than that of PGE2. The duodenal HCO3- secretory action of PACAP-27 as well as PGE2 was markedly potentiated by prior administration of isobutylmethyl xanthine (10 mg/kg, sc), the inhibitor of phosphodiesterase. Folskolin (250 micrograms/kg, iv), the stimulator of adenylate cyclase, also increased HCO3- secretion in the duodenum but not in the stomach. These results suggest that: 1) PACAPs are potent stimulators of HCO3- secretion in the duodenum but not in the stomach; 2) this action is mediated by cAMP through stimulation of adenylate cyclase; 3) cAMP is a mediator in duodenal but not gastric HCO3- secretion; and 4) PACAPs may be involved in the peripheral regulation of duodenal HCO3- secretion.
1-Methyl-3-isobutylxanthine↗
Association of selenoprotein P with testosterone production in cultured Leydig cells.
Selenoprotein P, a plasma selenoprotein, is thought to act as an antioxidant in the testis, similar to glutathione peroxidase. mRNA encoding selenoprotein P was selectively expressed by Leydig cells, suggesting participation in testosterone production. On the other hand, testosterone production has been linked to O2 toxicity in cultured Leydig cells. The authors, therefore, examined changes in selenoprotein P mRNA expression and testosterone production following stimulation by a stable analog cyclic adenosine 3',5'-monophosphate (cAMP) in cultured Leydig cells (MLTC-1 cells) under normal O2 concentrations. Selenoprotein P mRNA was analyzed by Northern blotting, while testosterone concentration in culture medium was measured by radioimmunoassay. When cAMP was added to cultures at 0, 0.01, 0.1, or 1 mM, selenoprotein P mRNA expression showed dose-dependent stimulation. cAMP was added at 0.1 mM to cultures, and the selenoprotein P mRNA expression and testosterone concentration were evaluated after incubation times of 2, 5, 9, 15, or 24 h. Selenoprotein P mRNA expression was maximal at 9 h. Testosterone concentration in the medium also increased, becoming maximal at 15 h. Selenoprotein P induced in Leydig cells following cAMP stimulation may counteract O2 toxicity from cAMP-mediated increases in testosterone production.
Animals↗
Outcome of surgical treatment for obstructive azoospermia.
The efficacy of reanastomosis was evaluated in 30 patients with obstructive azoospermia, including 19 postvasectomy cases; 7 cases complicating inguinal herniorrhaphy; 2 cases with a characterized isolated congenital anomaly; 1 case of Young's syndrome; and 1 case with an unknown, possibly congenital cause. In the postvasectomy group. successful vasovasostomy was achieved in 15 of 18 cases (83.3%; 1 postvasectomy patient dropped out of the study prior to analysis). Duration of obstruction in the 3 cases where anastomosis failed was 6, 9, and 20 years. In the group where obstruction followed inguinal herniorrhaphy, unilateral vasovasostomy was performed in 6 cases, and transepididymovasostomy was performed in 1 case. Success was achieved in 3 of 6 cases (50%; 1 case was not included because failure of spermatogenesis was detected postoperatively). In all 4 remaining cases, microsurgical epididymovasostomy or transepididymovasostomy was performed, but success was achieved only in the case of Young's syndrome. Although mailed questionnaires and telephone interviews indicated occurrence of natural pregnancy in only 4 affected couples, postoperative sperm counts were relatively satisfactory as in previous reports.
Adult↗
Effect of renal transplantation on sexual function.
This investigation was conducted to determine whether renal transplantation can improve sexual function in male patients with chronic renal failure. The authors retrospectively studied 121 men undergoing renal transplantation who complained of any type or degree of sexual dysfunction pre-operatively. Sexual function was evaluated by questionnaire which included erectile, ejaculative, and orgasmic functions. Pre- and postoperative frequency of sexual intercourse was also recorded. Patient characteristics, laboratory data, and endocrinologic profiles were analyzed to identify factors that might influence sexual function. In patients with hormonal determinations, results essentially normalized after transplantation. However, only 43 patients (35.5%) reported improvement of overall sexual function after renal transplantation, while 34 (28.1%) reported worsening. Although frequency of sexual intercourse was unaffected by transplantation, 15 of 20 patients who had no intercourse before transplantation initiated intercourse afterward. These 15 patients all underwent transplantation before 40 years of age. Comparisons of variables by sexual function showed significant differences for type of immunosuppressive treatment, interval after renal transplantation, and serum concentration of hemoglobin A1c. It is concluded that renal transplantation cannot improve sexual function in all patients, although hormonal profiles were largely normalized, and that renal transplantation should be encouraged at a younger age.
Adult↗
Bromocriptine for infertile males with mild hyperprolactinemia: hormonal and spermatogenic effects.
To clarify the influence of hyperprolactinemia on spermatogenesis and steroidogenesis in infertile male patients, the serum prolactin (PRL), luteinizing hormone (LH), follicle-stimulating hormone (FSH), testosterone, and estradiol concentrations were and the effect of bromocriptine treatment on spermatogenesis was examined. A total of 1234 patients were evaluated and 147 men had hyperprolactinemia. Of these, only 30 had PRL concentrations more than twice the upper limit of normal and most of them had a little excess over the upper limit. For 10 of these 30, serum hormone concentrations were measured and semen was analyzed before and after bromocriptine administration. No relationship between the PRL and other hormone concentrations was found. No changes were noted in the LH, FSH, testosterone, or estradiol concentrations, or in the sperm density and motility after treatment. The mean PRL decreased from 26.5 +/- 4.5 to 1.4 +/- 1.8 ng/mL. In infertile men who are mildly hyperprolactinemic, bromocriptine administration does not improve semen analysis, although it does normalize the PRL.
Bromocriptine↗
In-storage hypothermic perfusion for heart and lung transplantation.
The authors developed a new waterproof-packed infusion device for easy and sterile in-storage hypothermic perfusion during organ transportation for heart and lung transplantation. They examined the accessibility and efficacy of this infusion device for portable heart and lung preservation in canine transplant models. Sixteen heart and bilateral lung blocks were preserved by an in-storage hypothermic perfusion technique using the infusion device with University of Wisconsin solution. Of 16 dog recipients, 5 underwent orthotopic heart transplantation with cardiopulmonary bypass, and 5 dogs received left lung transplantation; the remaining heart and lung blocks were intrathoracically transplanted into 6 dogs. Functional status and histology of 11 heart and 11 lung allografts were evaluated by post-transplant course, hemodynamic parameters, arterial blood gas measurements, microscopic examination, and so on. Eleven transplanted hearts showed good cardiac performance and maintained systemic circulation after weaning from cardiopulmonary bypass. Eleven transplanted lungs had excellent respiratory function, and all five dogs with left lung transplantation survived for 5-46 days (mean: 18.8 days). These results suggest that in-storage hypothermic perfusion with this waterproof-packed infusion device can be a useful technique for long-term organ preservation in heart and lung transplantation.
Animals↗
A miniature intraventricular axial flow blood pump that is introduced through the left ventricular apex.
A new intraventricular axial flow blood pump has been designed and developed as an implantable left ventricular assist device (LVAD). The pump consists of a tube housing (10 cm in length and 14 mm in diameter), a three-vane impeller combined with a guide vane, and a DC motor. This pump is introduced into the LV cavity through the LV apex, and the outlet cannula is passed antegrade across the aortic valve. Blood is withdrawn from the LV through the inlet ports at the pump base, and discharged into the ascending aorta. A pump flow of > 8 L/min was obtained against 90 mmHg differential pressure in the mock circulatory system. In an acute dog model, this pump could produce a sufficient output of 200 ml/kg/min. In addition, the pump flow profile demonstrated a pulsatile pattern, although the rotation speed was fixed. This is mainly due to the changes in flow rate during a cardiac cycle--that is, during systole, the flow rate increases to the maximum, while the differential pressure between the LV and the aorta decreases to the minimum. Thus, this simple and compact axial flow blood pump can be a potential LVAD, with prompt accessibility and need for less invasive surgical procedures.
Animals↗
An internal thoracic artery homograft as a new small caliber vascular substitute.
The authors have examined the possibility of usage of an internal thoracic artery (ITA) homograft as a new small caliber vascular substitute. Left subclavian artery to left atrial appendage shunts with fresh ITA homografts (n = 6) or ITA autografts (n = 5) were made by modified techniques of coronary artery bypass grafting in mongrel dogs (body weight, 11-16.5 kg). All recipient dogs had no anticoagulant therapy or immunosuppression. Inner diameter of the grafts was between 1.4 and 2.0 mm. Blood flow in ITA grafts was measured by electromagnetic flow meter. The graft flow was 6-14 ml/min before harvest and 67-220 ml/min just after implantation, and there was no significant difference between groups. Flow in the ITA homografts decreased significantly compared with ITA autografts 1 month after operation, but five of six ITA homografts were patent. Histopathology of the grafts showed vascular rejection in the homograft group. These results suggest that an ITA homograft with postoperative immunosuppression might be a new small caliber vascular substitute for coronary artery bypass grafting in ischemic heart disease and the systemic-pulmonary shunt operation in congenital heart diseases.
Animals↗
Effect of additional intraaortic balloon support during weaning from a left ventricular assist system.
A safe and reliable method of weaning from a left ventricular assist system (LVAS) is necessary for successful circulatory support in patients with marginal heart failure. The purpose of this study is to assess the effect of additional intraaortic balloon (IAB) support during weaning from an LVAS by means of the LV pressure-volume relationship. A pneumatic LVAS with a sac-type blood pump was implanted in six adult mongrel dogs weighing 14 to 20 kg. All dogs had a drainage cannula placed in the left atrium and an outflow conduit in the ascending aorta. Hemodynamic parameters, pulmonary arterial flow, and pump output were monitored. An IAB was inserted through the groin. A conductance catheter and microtip manometer were inserted into the LV cavity. As a combination driving mode, LVAS ejection in the early diastolic phase and IAB inflation in the late diastolic phase were applied. After evaluation of baseline LV function, the pressure-volume relationship was repeatedly measured during change of driving modes as isolated LVAS, LVAS + IAB (1:1), LVAS + IAB (2:1), and isolated IAB supports. Finally, LV failure was introduced by stepwise ligation of left coronary arteries, and the LV pressure-volume relationship was measured in each driving mode. Under normal conditions, the pressure-volume loop showed no significant change among the four driving modes. In contrast, the LV pressure-volume relationship significantly improved according to the degree of additional IAB support on LVAS assistance under the condition of LV failure. These results suggest that additional IAB support might improve LV energy during weaning from an LVAS.
Animals↗
Determinants of clinical results of mechanical circulatory support for ventricular failure after cardiotomy.
To clarify determinants of clinical results of circulatory support for ventricular failure after cardiotomy, we examined 53 patients (33 men and 20 women) who underwent circulatory support for post operative heart failure from 1984 to October 1995. Their ages ranged from 22 to 74 years (mean, 51 years). In 53 patients, 32 had valvular, 19 had ischemic, and 2 had congenital heart disease. After operation, 21 patients underwent venoarterial bypass, 20 underwent biventricular bypass, and 8 underwent left ventricular bypass. The remaining 4 patients received a pulsatile left ventricular assist device. Weaning and discharge rates of the patients by type of support were 52.4% and 28.6% with venoarterial bypass, 75.0% and 55.0% with biventricular bypass, 87.5% and 37.5% with left ventricular bypass, and 75.0% and 50.0% with left ventricular assist device, respectively. The results of this series (67.9% weaning rate and 41.5% discharge rate) were acceptable. Peri-operative variables before and during circulatory support were analyzed multivariately by logistic regression analysis. Selected independent determinants (odds ratio) of significant difference (p < .05) were type of support (7.547) for non weaning and pre support cardiogenic shock (17.246), and type of support (8.780) and support duration (1.487) for mortality. These results suggest that early application before profound shock and appropriate selection of type of support might be key factors in successful circulatory support for ventricular failure occurring after cardiotomy.
Adult↗
Effectiveness of transaortic venting from a failing left ventricle during venoarterial bypass.
Insufficient unloading of the left ventricle (LV) is a limitation of percutaneous cardiopulumonary support (PCPS). We previously reported the unloading effect of transaortic catheter venting (TACV) during venoarterial bypass (VAB) in normal hearts. The aim of this study was to assess the effectiveness of TACV with VAB in a heart failure (HF) model. Seven adult mongrel dogs underwent TACV with VAB, and isolated LV failure was induced by multiple ligation of left coronary arteries. With standard hemodynamic monitoring, slope of the LV end-systolic pressure-volume relationship (Emax; mm Hg/ml), aortic elastance (Ea; mm Hg/ml), LV stroke work (SW; 10(-4)J), preload recruitable stroke work (PRSW; 10(-4)J/ ml), LV pressure-volume area (PVA; 10(-4)J), and potential energy (PE; 10(-4)J) were assessed using a micro-tip manometer and a conductance catheter. In addition to evaluation of LV function, myocardial adenosine 5'-triphosphate (ATP) was measured in each condition. The TACV combined support significantly reduced LV total energy (PVA) and LV work (SW). The LV energetic charge (PE/PVA, myocardial ATP) was significantly increased by TACV. These results suggest that TACV might be an effective technique for LV recovery during VAB or PCPS in patients with severe heart failure.
Animals↗
Direct cardiac potential trigger for chronic control of a ventricular assist device.
As a new trigger method for chronic drive control of a ventricular assist device (VAD), a direct cardiac potential trigger was assessed under various conditions in a chronic experimental model. A pneumatic pulsatile VAD was implanted as circulatory support between the left ventricular apex and the ascending aorta in 12 adult pigs. Hemodynamic parameters and pump output were continuously monitored. Two tips of a bipolar electrode were set on the RV anterior wall and the LV posterior wall for recording direct cardiac potential. Counterpulsation drive of the VAD was applied by using the R wave in a standard electrocardiogram (ECG) or the direct cardiac potential as an ECG trigger. As special conditions, various artifacts on ECG, electromusculogram, arrhythmia, irregular ventilation, and passive vibration (simulation of exercise) were set for assessing the ECG trigger modes. Artifacts of irregular ventilation and passive vibration made the drive control poor using a standard ECG trigger. In contrast, the direct cardiac potential trigger maintained the counterpulsation control of the VAD well in all conditions of this study, and was a safe and reliable support for the native heart. It also supported animals for up to 48 hours after operation. The above results suggested that the direct cardiac potential trigger might be useful for monitoring native heart beats and adjusting the support cycle to the native heart cycle as a chronic control method for various VADs.
Animals↗